There is a growing demand, in recent years, for antenna duplexers constructed by combining transmission filter and receiving filter which are component parts of portable phone. And features of compact size and high performances are required of antenna duplexers.
FIG. 6 indicates a conventional surface acoustic wave filter. The surface acoustic wave filter indicated in FIG. 6 is constructed by having surface acoustic wave resonators R1, R2 connected in series and surface acoustic wave resonators R3, R4 grounded through bonding wires 114, 115.
As such surface acoustic wave filter is known Japanese Laid-Open Patent Application No. H6-164309, for example.